带有字符串列表的拆开/平坦的不平衡列表

Question

鉴于这种情况，我有以下列表：

['graph_edges', ['graph_nodes'], ['graph_nodes'], ['graph_edges2', ['graph_nodes2'], ['graph_nodes2']]]

我希望将其转换为类似的内容：

['graph_edges', 'graph_nodes', 'graph_nodes', 'graph_edges2', 'graph_nodes2', 'graph_nodes2'] 
# I would list(set(thislist)) afterwards

已经有很多解决方案，但奇怪的是，对于我的情况，我无法完成任何有意义的事情：

from functools import reduce
import operator
reduce(operator.concat,['graph_edges', ['graph_nodes'], ['graph_nodes'], ['graph_edges2', ['graph_nodes2'], ['graph_nodes2']]])
*** TypeError: can only concatenate str (not "list") to str

与 sum 相同：

sum(['graph_edges', ['graph_nodes'], ['graph_nodes'], ['graph_edges2', ['graph_nodes2'], ['graph_nodes2']]], [])

这单行展开太多：

> [item for sublist in ['graph_edges', ['graph_nodes'], ['graph_nodes'], ['graph_edges2', ['graph_nodes2'], ['graph_nodes2']]] for item in sublist]
['g', 'r', 'a', 'p', 'h', '_', 'e', 'd', 'g', 'e', 's', 'graph_nodes', 'graph_nodes', 'graph_edges2', ['graph_nodes2'], ['graph_nodes2']]

或者与itertools：

>!list(itertools.chain(*lol))
['g', 'r', 'a', 'p', 'h', '_', 'e', 'd', 'g', 'e', 's', 'graph_nodes', 'graph_nodes', 'graph_edges2', ['graph_nodes2'], ['graph_nodes2']]

免责声明：我在ipdb中尝试过这些，所以总是有可能出现错误

我当前（不起作用）且非常不满意的解决方案是这里：

retlist= []
dedefined=['graph_edges', ['graph_nodes'], ['graph_nodes'], ['graph_edges2', ['graph_nodes2'], ['graph_nodes2']]]

for element in dedefined:
    if isinstance(element,list):
            retlist+=self.getSingleElement(element)
        else:
            retlist.append(element)
    return list(set(retlist))

@classmethod
def getSingleElement(cls,element):
    if isinstance(element,list):            
            return cls.getSingleElement(*element)
    else: return element

当element达到< code>['graph_edges2', ['graph_nodes2'], ['graph_nodes2']] 它失败了，但我无法想到有意义的东西。我可以制作一个生成新值而不是返回值的生成器，或者迭代每个元素并使其成为一个可以溶解的列表。但这些想法都不能让我信服

Answer 1

您需要使用递归来考虑列表可以任意深度嵌套的事实：

def flatten(lst):
    result = []
    for item in lst:
        # You can use:
        # if not isinstance(item, list):
        # if you have other items besides integers in your nested list.
        if isinstance(item, str):
            result.append(item)
        else:
            result.extend(flatten(item))
    return result

此输出：

['graph_edges', 'graph_nodes', 'graph_nodes',
 'graph_edges2', 'graph_nodes2', 'graph_nodes2']

Answer 2

def flatten(array):
    flat = []
    for member in array:
        if isinstance(member, (tuple, list)):
            flat.extend(flatten(member))
        else:
            flat.append(member)
    return flat